Method for treating a fibrous material



P 6, 1955 B. ARMSTRONG R 2,717,195

METHOD FOR TREATING A FIBROUS MATERIAL Filed Aug. 2, 1954 I7 73 63 e9 64 c2 68 u H 65 la\ 7 1 4 R I I 5G I 37 5g 72 m &4;

BRUCE ARMSTRONG 72 3nvntor fi 3 66 v a.

attorney United States Patent 0 METHOD FOR TREATING A FIBROUS MATERIAL Bruce Armstrong, Saginaw, Mich., assignor to Jackson and Church Company, Saginaw, Mich., a corporation of Michigan Application August 2, 1954, Serial No. 447,371

18 Claims. (Cl. 8-156) This invention relates to a method for treating a fibrous material with a treating agent, particularly to a continuous method for treating a bulk fibrous material characterized by a high degree of utilization of the treating agent, a high degree of uniformity of treatment of the individual fibers and by the ease and rapidity with which the method can be carried out. This application is a continuation-in-part of co-pending application Serial No. 204,039, filed January 2, 1951.

The treatment of bulk unoriented fibrous materials with agents to obtain desired effects is carried out widely in industry. Such treatments include washing, cleaning, conditioning, bleaching, coating, oiling and dyeing of fibers as well as actually causing the fibers to react chemically with specific agents. Typical instances of such treatments are the scouring of wool, the washing of cotton, the bleaching of wood pulp, the preparation of alkali cellulose, and the like. Fibrous products which are often processed in bulk include cotton, wool, ramie, bagasse, linen, wood pulp and synthetic staple fibers, such as nylon, rayon and others.

The treatment of masses of unoriented fibers offers certain difiiculties. Because of the tendency of the loose fibers to become entangled and to mat together, it is almost impossible to effect a uniform and rapid treatment of them, e. g., with a liquid, unless they are agitated during the treatment to bring fibers unexposed to the treating agent into a more advantageous position for contacting the agent. Certain fibers, such as those of wood pulp, ramie, linen and the like, are obtained in usable form from their naturally occurring state by processes, e. g., by cooking, retting, digestion and the like, which often leave the fibers unseparated completely from one another but rather as small bundles, each consisting of many closely packed, longitudinally parallel fibers. The difficulty of causing treating agents to penetrate such bundles rapidly and completely is Well known.

The difficulty is aggravated in the case of-many natural fibers by the relatively high adsorptive capacity ofthe fibers for many substances which are desirable treating agents, the net result often being that the fibers contacted first or most easily by the treating agent are over-treated and those contacted with the most difficulty are greatly under-treated. Furthermore, it is essential in most instances that the treatment of bulk fibers be carried out in such a way that they are not broken unduly because their usefulness is often related directly to the average length of the individual fibers. The importance of this is well known, especially in the paper and textile industries.

The treatment of bulk fibrous materials has heretofore often been carried out using a liquid, generally water, as a dispersing agent for the fibers and as a solvent or dispersant for the actual treating agent. The mass of fibers is often first dispersed as well as possible in the liquid by agitation to form a readily flowable slurry and the treating agent then added gradually to the stirred mixture. In other instances, especially when masses of long fibers are involved, the masses are alternately squeezed and allowed to relax beneath the surface of a treating liquid or solution. Variants of the processes just mentioned have been developed which are intended for the treatment of particular fibers to produce specific results.

Conventional methods for treating bulk fibrous products have many disadvantages which it has not hitherto been possible to overcome. The proportion of water, or other liquid, which must be mixed with most fibers to produce a flowable composition is generally large compared with the proportion of fibers. Such flowable slurries of wood pulp in water, for example, generally contain not more than about six to ten per cent, or even less, by weight of fibers on a dry basis. This requires the utilization of large quantities of water, with the attendant ,costs of water treatment and handling, and the provision of large equipment units for the treatment of relatively small amounts of fiber. persion of matted fibers in a liquid to form a smooth, uniform suspension is not accomplished easily and often requires prolonged stirring and beating of the mixture. The recovery of the fibers from such mixtures presents considerable difficulty in the avoidance of fiber loss and in the reduction of the water content of therecovered fibers to values desirable for many purposes.

The employment of such large proportions of fluid in the treatment of 'bulk fibers is also disadvantageous insofar as the actual treatment itself is concerned. Most such treatments involve the actual removal of a treating 7 exist both for the reaction to proceed rapidly and for it to proceed to a substantial degree of completion before equilibrium is reached. These considerations become of a great deal of importance in conventional processes for treating bulk fibers wherein the fibers are dispersed in a relatively large amount of a dilute solution of the treating agent. In the bleaching of wood pulp, for example, using conventional low density procedures, the mixture generally contains not more than about six per cent by weight of fibers and a small fraction of one per cent of bleaching agent. Under such conditions, a considerable proportion of the bleaching agent remains unused in the solution unless the treatment is carried on for an uneconomically long period of time. This difiiculty is generally compensated for by using an excess of the bleaching agent and discarding to waste the unused portion of the agent. In addition, the degree of bleaching attained using such dilute solutions is not generally as great as would be possible using the same bleaching agent but in a more concentrated form. Other comparable fiber-treating processes suffer from the same disadvantages. In most instances it is uneconomic to recover unused treating agents from such mixtures and any amount of agent used over that theoretically necessary to accomplish the desired result is wasted.

Efforts have been made to overcome the disadvantages of conventional fiber-treating processes mentioned. These have usually consisted essentially in attempting to use a lower proportion of liquid compared to the amount of fibers in the mixture and in manipulating The even disthe mixture in such a way as to still insure as rapid and complete contact as possible of the: treating fiuid with all of the fiber surfaces throughout the mass. Such procedures have proved of some value but have not overcome the basic ditficulties referred to. Thus, in the bleaching of wood pulp previously mentioned, some success has been attained using the so-called high density processes wherein the mixture of fiber and water may contain up to from 20 to 30 per cent, or even somewhat more, of fiber. Although such high density processes can be carried out with an increase in the overall efficiency of utilization of the bleaching agent, particularly when a peroxide bleach is used, and with the production of a somewhat higher yield of pulp having a better brightness than is usually accomplished economically using a. conventional low density procedure, the use of such high ratios of fiber to water presents diificulties not encountered in low density bleaching processes.

It is Well known that wood pulp containing as little as 40 per cent of actual fiber on a dry basis does not form a slurry which can be handled as a liquid. It can neither be pumped through a pipe nor stirred in a tank using conventional agitators and must, therefore, be handled substantially as a solid. Slurries containing as little as 20 to 30 per cent of fibers are so thick that power requirements for agitating them thoroughly are excessive. In addition, the difficulty of mixing a relatively small volume of one liquid, e. g., of concentrated bleach, uniformly throughout a large volume of a thick 0 or viscous liquid or slurry are well known. In the high density processes for bleaching wood pulp, the ditficulties of securing uniform distribution of the bleach throughout the fibrous mass so that it contacts all of the fibers quickly and in the desired concentration in the water present are increased enormously as compared with the low density methods.

These same types of difficulties, illustrated in the high density bleaching of Wood pulp, persist in substantially all of the methods which have been proposed for treating fibers in bulk form which involve reducing the proportion of liquid medium over the proportion generally used in conventional processes. it is readily apparent that the present status of the art of treating unoriented bulk fibrous substances leaves much to be desired with respect to the ease and convenience of the operation, the degree of utilization of the treating agent, the avoidance of waste liquor disposal and the size and cost of the equipment which must be used. It is equally apparent that a new method whereby an improvement with respect to any one or more of these factors could be realized would be of great value.

The present invention is concerned with a method, first described in the parent application referred to, wherein bulk fibrous materials can be treated with a treating agent under conditions which eliminate substantially entirely the necessity of a liquid phase being present in the treating zone, wherein uniform and substantially complete contacting of all surfaces of the fibers with the treating agent is obtained rapidly using simple equipment and wherein the conditions prevailing in the treating zone and the proportions of fiber and treating agent can be controlled precisely to insure adequate uniformity and reproducibility of results. In addition, the method permits the use of a minimum amount of treating agent in high concentration, thus effecting the desired result quickly and economically and with the utilization of substantially all of the treating agent employed and the elimination, in large measure, of the necessity for disposing of waste liquors.

In accordance with the method of the present inven tion, a fibrous substance consisting of unoriented or bulk fibers is forwarded through a fiber-separating and fiber-treating zone, wherein it is subjected to a mechanical fiber-separating action of progressively increasing incharged from the separating and treating zone and utilized or processed further in any desired manner.

Although the process may be though of primarily as a process for coating fibers with a treating agent, it is pointed out that in many instances there appears to be an actual penetration of the agent beneath the surfaces of the fibers subsequent to the contacting of the agent with the fibers. Such penetration may proceed more or less rapidly, depending on the particular fibers and the particular treating agent employed. The particular degree of mechanical fiber-separating action exerted in the separating and treating zone also appears to effect the degree and rapidity of penetration of the fibers by the treating agent. This is probably due to the vigorous and extensive flexing of the individual fibers which usually occurs within the zone following the contacting of the treating agent with the fibers. It appears that the'more vigorous and the more extensive the flexing of the fibers within the zone, the greater is the degree of penetration of a particular fiber by a particular agent. In any event, such penetration, which appears to be beneficial in many cases, is contemplated as one of the possible, but not essential, elfects often secured by the process even though the effect is, for convenience, generally referred to as a coating effect.

The fiber-separating action referred to as being effected in the fiber-separating zone comprises not only the separating or tearing apart from one another of the fibers introduced into the zone as bundles of adherent fibers but also the separation to a high degree of individual fibers which are in only physical contact with one another. The fibers are thus, in effect, floated in a gaseous atmosphere, usually air, in the zone and are slid rapidly along one another under ideal conditions favoring the contacting and spreading of the highly dispersed treating agent over substantially the entire surface of each fiber. One suitable mechanical means for effecting the fiber-separating and fiber-treating operations will be described later.

A desirable feature of the invention is the possibility of maintaining a suitable atmosphere within the treating zone. Substances which are sensitive to oxygen can, for example, be treated in a zone in an atmosphere of nitrogen, carbon dioxide or other suitable gas toward which the substance is stable. Steam or a suitable heated gas can be introduced into the zone to control the treating temperature to a precise and desirable value.

The method of the present invention is based, in part, upon the concept that the treating'of a fiber, whether it be merely to coat the fiber with a conditioning agent or to effect a desired chemical reaction, e. g., destruction by bleaching of a component or impurity associated with the fiber or esterification of the actual fiber itself, depends primarily upon the contacting of as nearly all of the surfaces of the fiber as uniformly as possible with the agent employed. This is readily apparent in the case of conditioning agents which depend for their effect only upon the deposition of a layer or film of the agent on the fiber surfaces. It is apparent that this is also the case in treatments involving a chemical reac:

tion when it is noted that almost invariably, because of the insolubility in the treating solution of the fibers and of substances associated with them, the reaction occurs at the surface of or even Within the body of the fiber and that the sole function of the liquid medium in conventional fiber-treating processes is to disperse the treating agent and to bring it into contact as uniformly as possible, but, unfortunately, in greatly diluted form, with the surfaces of the fibers. It is thus seen that the result which must be effected in substantially any fiber-treating process is the contacting of the treating agent uniformly with the surfaces of the fiber and in as nearly the amount per unit of fiber surface area as is required to give the desired effect. It is, therefore, obvious that the provision of a fiber-treating method which would effect this result and which would at the same time avoid the necessity of using a liquid medium for suspending the fibers would overcome many of the difficulties inherent in the heretofore known methods.

Particular attention is directed to the advantages of the new method. The method avoids entirely the loss of fibers usually experienced in recovering fibers from a dilute slurry. As a matter of fact, there is usually no loss of fibers in operating the process other than such minor losses as may occur from time to time from improper design or operation of the equipment used in carrying out the process. The amount of treating agent used per unit of fiber need be no more than the precise amount necessary to produce the desired effect, with a consequent sav ing in cost of the agent. The use of only the necessary or theoretical amount of the agent avoids, in many instances, the necessity of washing the fiber to remove therefrom unused agent which might subsequently damage the fibers or which might be undesirable in subsequent processing of the fibers.

Because of the concentrated form in which the treating agent can be caused to contact the fibers, the effect produced by the agent occurs to the maximum extent and at a rapid rate. Furthermore, because of the highly uniform nature of the distribution of the agent on the fibers, it is not necessary that the fibers be retained in the fiberseparating and fiber-treating zone until the action of the agent has entirely ceased. Such action can proceed after the treated fibers have been discharged from the zone, i. e. during transport or storage.

Because of the rapidity with which the fibers are for warded through the zone, a relatively small equipment unit can serve for the treatment of a relatively large amount of fiber per unit of time. The power cost per unit of fiber treatment is correspondingly low. In'instances where washing or other treatment of the fibers with a liquid following their treatment by the process of the invention is desirable, the fibers are in a highly satisfactory state for the operation because of their very uniform bulk density and because of the substantially complete separation of each fiber from the others. Under such conditions, the dispersion of the fibrous mass in a liquid, e. g., in water, to effect a smooth slurry of desired consistency can be effected readily with a minimum of agitatingand beating. When the process is properly operated, the treated fibrous product is essentially free of bundles of adherent fibers.

it has been mentioned that the fibers are contacted intermediate the ends of the fiber-separating and fibertreating zone with a fiber-treating agent in highly dispersed form. Although the treating agents employed in the process are generally liquid agents or solutions of solid agents in a liquid solvent, e. g., in water, the process is adaptable to the utilization of finely powdered solid agents'and ,also of gaseous agents. The treating agent is introduced into the fiber-treating zone in any convenient manner, preferably at a rate which is substantially uniform with respect to the rate at which thefibers are introduced into the zone. When the treating agent is a iquid, it is generally sufiicient to merely add the liquid as one or more continuous streams which are run onto the violently agitated fibers as they are being forwarded through the zone. Because of the very high degree of agitation of the fibers which is generally maintained, the

'6 liquid is immediately-atomized and converted into avery finely divided spray or mist. Alternatively, .the liquid can be atomized outside the zone to form a mist which is then introduced into the zone or the liquid can be forced through an atomizing nozzle directly into the Zone. The particular way in which a liquid treating agent is intro duced ino the zone is not critical except insofar as the conversion of the liquid to a finely divided mist must be effected either prior to or immediately upon contact of the liquid with the fibers. Gaseous treating agents,

of course, offer no difliculty insofar as their dispersion. is

concerned and solid agents which are very finely ground are distributed uniformly throughout the fibrous mass when simply added at a uniform rate to thefibrous mass as it travels through the zone.

gln some instances, especially in the bleaching of pulp, it has been found that the preferred procedure involves the adjustment of the conditions Within the zone to provide for the substantially complete separation of the fiber bundles into individual fibers by the time the fibrous mass has progressed through the zone approximately to the region where the treating agent, e. g., the bleaching agent, is added. When operating in this manner, the agent is,- in effect, added to a vigorously agitated mass of substan- I tially individual fibers which are in a condition approachfound in the bleaching of wood pulp that by operating in the manner just described the amount of bleach which need be used to secure a given improvement in brightness ofthe pulp may, unexpectedly, be decreased by as much as 25% or morefrom the amount which must be employed'to obtain the same increase in brightness but in-' troducing the'bleach into the fiber-separating zone nearer the point of entry of the fibers into the zone and where the bundles ofadherent fibers have not been separated nearly so completely into individual fibers. Furthermore, not only is the amount of bleach which need be used reduced greatly but the bleaching action is much more uniform. For this reason, the preferred procedure involves introducing the treating agent into the treating zone at a point or points within the zone sufiiciently removed from the point of entry of the fibers into the zone where' tion. of liquid treating agent added is not generally 'suffi-- cient to form a treated product which has any appreciable or significant proportion of liquid phase product in the mass. The process can, however, be operated, if desired,

so that the amount of, liquid agent added is sufiicient to yield 21 treated product having a certain amount of a liquid phase entangled with and distributed through the treated fibrous mass. It is often advisable, however, to avoid introducing enough liquid phase treating agent into the fibrous mass to yield a treated product which is either in the nature of a slurry or from which'liquid can be squeezed under moderate pressure, e.- g.,d uring storage and transporting.

lt has been pointed out previously that in most fiber treating processes it is desirable to avoid as far as possiblethe breaking of the fibers. It is thus advisable in the operation of the process to provide for subjecting the fibers immediately after they enter the fiber-separating zone to a relatively mild fiber-separating action whereby the larger bundles of fibers are broken down into smaller bundles which pass immediately to the next region of the zone wherein they are subjected to a somewhat more vigorous fiber-separating action. By increasing the intensity of the fiber-separating action progressively and substantially uniformly as'the fibers travel through the zone, the fibers are subject to the most vigorous fiberseparating action for only a very short-time just prior to their discharge from the zone. Inasmuch as breakage of the fibers increases very rapidly as the degree of the mechanical fiber-separating action is increased, it is possible by following the procedure just outlined to secure the maximum separation of the fibers from one another with a minimum of fiber breakage even when the fiber feed contains a relatively high proportion of bundles of adherent fibers. The separation of fibers which areonly in'physical contact with one another occurs generally throughout the zone but is at a maximum, and the fibers approach a floating condition to a greater degree just prior to their discharge from the zone.

' It is apparent that it is impossible to give any precise statement of the degree of fiber-separating action which must be maintained in the fiber-separating zone because this'will depend upon a number of factors including the nature and condition of the fibers, their previous treatment,-the precise nature of the mechanical fiber-separation action employed and upon other factors. ]t is, however,- apparent that the suitableness of the degree of fiber-separating action employed in any instance can be judged quickly by an inspection of the treated fibrous mass and that the degree of fiber separation can be altered quickly to obtain a product having a desired degree of fiber separation but not an undesired degree of fiber breakage.

' It has been mentioned previously that the treating agent is introduced into the fiber-separating and fiber-treating zone at a location intermediate to the ends of the zone. It follows that the agent is thus introduced at a location where the fibers have already been subjected to the minimum degree of fiber-separating action effected in the zone and are thus in violent agitation but where they have not been subjected to the maximum degree of fiber-separating action effected in the zone. By introducing the treating agent into the zone at such a location, its atomiztion and rapid distribution throughout the mass is assured by its contact with the fibers which are already under violent agitation. On the other hand, because the fibers undergo even-more violent agitation after the introduction of the treating agent, the distribution and spreading of the treating agent over substantially all of the surface of each fiber is assured. Any portions of the surface of an individual fiber which at first remain uncoated with the treating agent are subjected during the following more violent agitation of the mass to a wiping action by the surfaces of adjacent fibers carrying a coating of the treating agent. At the same time, any unevenness of the coating on the fiber surfaces tends to be smoothed out and equalized by the wiping action of the fibers against one another. 7

Generally speaking, the treating agent is introduced into the fiber-treating zone at a location between about 25 per cent and about 85 per cent of the distance through the zone, measured from the point of entry of the fibers into the zone. if desired, a multiplicity of ports or nozzles can. be employed through which the treating agent is introduced into the zone. ever, that the invention is not limited as to the precise location of the means for introducing the treating agent into-the treating zone and that this location Will depend to some extent upon the nature of the'fiber being treated, the nature and proportion of the treating agent employed and upon the particular type of mechanical fiber separation used.

The process of the invention can be employed in treat ing a. widevariety of-bulk' fibrous products including wood pulp, bagasse, ramie, linen, cotton staple fiber, cot- It is apparent, how-- ton linters, wool and synthetic staple fibers, such as rayon, nylon and the like. Generally speaking, the process is of particular value in the treatment of wood pulp, bagasse, ramie and similar cellulosic fibers. The process is not adapted to the treatment of the so-called monofilaments which may consist of individual filaments many feet or many yards long.

Treating agents which can be employed include aqueous solutions of hydrogen peroxide, alkali'metal hypochlorites and chlorites, and other bleaching agents, powdered or concentrated aqueous alkalies, e. g., in the production of alkali cellulose, humectants, such as glycerine or a glycol, oils, aliphatic acid'anhydrides, e. g., in the production of cellulose esters, gaseous chlorine, water, e. g., in the adjustment of the water content of fibers and as a step preliminary to pressing to extract soluble constituents of the fibrous mass, and others.

In certain instances wherein the washing or scouring of fibers, e. g., with a soap or a detergent, is involved,

it is advantageous to carry out the process herein described using a relatively concentrated solution of the soap or detergent as the treating agent and subsequently to rinse the soap or detergent out of the treated fibrous product with water. In this way an efficient contacting of the strong soap solution with substantially all of the fiber surfaces is effected rapidly and economically. The violent agitation of the fibers coated with the strong soap loosens particles of dirt and other foreign substances from the fibersurfaces to a degree not readily attainable by conventional washing procedures except after prolonged agitation or even boiling with dilute soap solutions. Because of the uniform bulk density of the treated fibers, the soap and suspended dirt particles can be washed readily from them with a considerable saving in water and size of equipment over that required for conventional scouring operations.

It is also advantageous in certain'instances to utilize the process in connection with the dyeing of bulk fibers. In such an instance, a relatively concentrated solution of the dye is used as the treating agent and the treated fibers subsequently rinsed, e. g., with water or salt solution, to remove unfixed dye. Multiple treatments of fibers in the same zone can be carried out using the process by treating the fibers first with one treating agent and subsequently with another treating agent as the fibers are forwarded through the zone. This is well exemplified by the bleaching of wood pulp using a combination of, a chlorite and a hypochlorite wherein the pulp is treated firstwith a solution of sodium chlorite in one region of the zone and then with a solution of sodium hypochlorite in another region of the zone. A variation of the process contemplates forwarding the fibers through a first fiberseparating and fiber-treating zone as herein described wherein they are treated with one fiber-treating agent and subsequently, either immediately or after transport or storage of the fibers, forwarding the same fibers through a second similar zone wherein they are'treated with a second fiber-treating agent. It is apparent that in such an instance the fiber-separating action in the second zone,

unless it is more vigorous than that in the first zone, usually consists principally of separating from one another fibers which are only in physical contact with one another rather than the tearing apart of bundles of adherent fibers. In a special instance, mordant dyes can be employed by treating the fibers with a dye at one location in the fiber-treating zone and with a concentrated solution of a mordant at another location in the zone nearerthe point of discharge of the fibers from the zone. Other variations of the process will be apparent to those familiar with the arts Any suitable equipment can be employed in carrying out the process provided only that it is adapted to the creation within the fiber-separating and fiber-treating zone of action and to the contacting of a treating agent with the fibers at a location intermediate the ends of the zone. It is apparent that, because of the different natures and different physical characteristics of dififerent bulk fibrous substances, the particular equipment used in treating a particular fiber will depend to some extent upon the nature of the particular fiber. Generally speaking, however, an apparatus which is suitable for the treatment of one fibrous product can, by simple modification, be adapted to the treatment of another fibrous product.

By way of illustration, there is shown in the accompanying drawing an apparatus, described and claimed in the parent application, which is well adapted to carrying out the bleaching of wood pulpwith hydrogen peroxide employing the herein described process. It is to be un derstood, however, that the present invention is not limited as to apparatus or as to the treatment of any particular fibrous product or as to the use of any particular treating agent and that the apparatus described, as well as the description of its utilization in the bleaching of wood pulp with hydrogen peroxide, are given only by way of illustration.

In the drawing referred to wherein, in the interest of clarity, certain features are shown on a somewhat exaggerated scale,

Figure 1 is a sectional elevation of an apparatus useful in carrying out the process of the invention and including closely spaced members having non-planar surfaces, one of which is adapted for rapid movement relative to the other.

Figure 2 is a top plan view of a section of a non-planar surfaced member of the apparatus of Figure 1, and

Figure 3 is a sectional elevation of a section of Figure 2.

The apparatus illustrated in Figure 1 of the drawing includes a stationary housing functioning in part as a supporting frame and which, for ease in assembly, is preferably formed of a top section 11, an intermediate section 12 and a base section 13, the sections being secured together as by bolts 14 and 15 extending through suitable peripheral flanges formed on the housing sections. The central housing section 12 is formed with a transverse member 16 adjacent its upper end to provide a circular trough around a central port, the purpose of which will be apparent as the description proceeds. The top section 11 of the stationary housing is formed with a large central feed port 17 for introduction of pulp into the apparatus by any suitable and conventional feeding device, not shown. The underside of the top housing section 11 is suitably contoured to form an inverted circular trough around the port 17 in register with the circular trough in the transverse member 16 to provide a peripheral conduit through which pulp can. be forwarded from within the apparatus to an exhaust port 18 at the side of the apparatus.

The transverse member 16 of the intermediate housing member 12 is further formed with a depending section 19 integral therewith prolonging the central bore. An additional, generally tubular, stationary member, or annular ring, 22 is also provided which is secured as by bolts 23 to the underside of the transverse member 16 encircling the depending section 19. The lower end of the generally circular member 22 is provided with a centrally bored end plate 24 which is secured to the member 22 as by bolts 25 or in other convenient manner. The central bores of the member 19 and of the member 24 are formed to provide elongated bearing surfaces 26 and 27, respectively, on their inner surfaces.

An axially slidable, generally tubular, housing 29 is positioned within the central bores of the members 16, 19 and 24. The outer surface of the tubular housing 29 is provided with external bearing surfaces adjacent its upper and lower ends to bear on the bearing surfaces 26 and 27, respectively. Rotation of the housing 29 is prevented by means of a suitable key 34 lying in suitably formed registering slots formed in one of the bearing surfaces 26 and 27 and the corresponding external bearing surface on the member 29.

A central shaft 28 extends axially through the slidable housing 29 and is rotatably mounted therein as by means of bearings 32 and 33 adjacent each end of the housing, the shaft being secured against end play within the housing 29 in any convenient or conventional way, e. g. by a collar 61 near the upper end of the shaft and integral therewith and a lock collar 30 adapted to be secured to the shaft below the lower bearing 33. r The central shaft 28 is equipped at its lower end with a pulley 78'or other suitable means by which it can be rotated from a power source, not shown. 5 1

Suitable means are provided for adjusting accurately the vertical position of the slidable housing 29 with respect to the bearing surfaces 26 and 27 and for holding it firmly in this position following the adjustment. One such suitable means characterized by ahigh degree of accuracy and fineness of adjustment includes a tubular.

non-rotatable elevator screw 35 encircling the slidable housing 29 intermediate the bearing surfaces 26 and 27.

In a preferred embodiment, the annular elevator screw 35 has an internally directed flange 37 at its lower end and is provided with external screw threads of rectangular cross-section. This elevator screw is encircled andits threads engaged bythe internally threaded, annular, elevating sleeve 46. This latter is free to rotate with respect to the frame of the machine but is held axially by the top flange 47 and the worm wheel 49 (to which latter it is attached by cap screw 52) snugly engaging the annular stationary ring 48 which is formed on the inner side of the housing member 22.

Fins 36 extending downwardly from the annular mem ber 19 engage corresponding openings in the top flange of elevator screw 35 and prevent rotation of said elevator screw with respect to the frame of the machine but permit axial movement with respect thereto.

A heavy coil spring 39 inside the elevator screw 35, rests on the flange 37 and exerts pressure against the shoulder 38 of the member 29, which latter is free to slide axially within bearing member 19. The normal operating position of the member 29, and the parts sup-,

ported thereby, is determined and limited in a downward direction by the strength of said spring 39 and in an upward direction by an adjustable collar 42 which is held in position by the set screw 43. Thus, the member 29, together with the shaft, shaft bearings and the disk 57, continually float on the spring 39. In the event tramp metal or other hard, foreign object, should enter into the machine with the pulp, the spring 39 will yield and permit the disks to separate sufficiently to pass said object therebetween without damaging the teeth thereof, the bearings, or other parts. When the foreign object has passed, the disks will return to their original position.

Bearing surfaces 53 and 54 are provided on the outer surface of the elevating sleeve 46 between the flange 47 and the worm wheel 49 and on the inner surface of the inwardly extending ring member 48 to maintain the elevator screw 35 and elevating sleeve 46 in an accurately centered position.

Rotation of the elevating sleeve 46 is effected as desired by means of a worm 55 meshing with the teeth of the worm wheel 49, the worm 55 being secured to a horizontal shaft 56 which extends through the outer housing 13 of the apparatus and is equipped at its outer end with a hand wheel, not shown. Adjustment of the central shaft 28 in an upward or downward direction is thus elfected with ease and with greate precision by rotation of said hand wheel. At the same time, any vibration and movement of the central shaft 28 out of accurate alignment is prevented by the heavy and elongated bearing surfaces 26 and 27 in which the slidable housing 29 slides, so that the fine adjustment of the central shaft 28 is not destroyed at high speeds of rotation under heavy load.

A heavy horizontal rotor plate 57 is keyed, as by a key 60, on the upper end of the central shaft 28 in abutment on its lower side with a collar 61 integral with the shaft. A cover plate 58, centrally bored to accommodate the collar 61, is secured as by bolts 59 on the top end of the slidable housing 29 effectively preventing the entry of water, dirt or other foreign matter into the housing 29 and the bearings 32 and 33 therein. A cap cone 62 is secured to the upper end of the central shaft 28 as by a bolt 63 to hold the rotor plate 57 firmly against the collar 61 and is formed on its top surface to provide a smooth outwardly and downwardly sloping surface along which pulp introduced into the apparatus through the port 17 can slide without retardation. A series of vanes 64, usually two to five in number, are on the cap cone 62 and serve, upon rotation of the central shaft 28, the plate attached thereto and its accompanying cap cone 62, to forward pulp radially outwardly to enter between the upper surface of the plate 57 and the lower surface of the housing member 11. A series of fins or paddles 65 are secured around the periphery of the plate 57 which convey the so-forwarded pulp to the discharge port 18 and discharge it from the machine.

The outer section of the upper surface of the rotor plate 57 is formed to receive a shredder plate 66 which is secured thereto as by a series of bolts 67. The inner or under surface of the upper housing member 11 is similarly formed to receive a second or upper shredder plate 68 which issecured thereto as by bolts 69 in a position facing the lower shredder plate 66. The upper shredder plate is thus stationary while the lower shredder plate is rotatable. The facing surfaces of the shredder plates 66 and 68 converge radially outwardly and are provided with a series of teeth or impacting elements 72 as shown more clearly in Figures 2 and 3. impacting element on the lower shredder plate is formed with its leading face vertical and substantially in the form of an isosceles triangle having a horizontal base. The lateral surface of each of the impacting elements is preferably normal to its leading face for a short distance rearwardly therefrom to provide a sturdy plate and each plate is rigidly braced by projecting each of its trailing edges inwardly and backwardly to a point substantially in a plane including the base of the isosceles triangle and normal to the leading face of the element.

The impacting elements are formed in rows each lying on an arc of rotation of the rotor plate 57 and each tooth in each row having substantially the same dimensions. The teeth in each successive row are smaller in each of their dimensions, and lie closer together in the r row, than the teeth in the next adjacent row nearer the center of rotation of the rotor plate 57. In certain of the outer rows the vertical leading face of one element often intersects the trailing section of the tooth next forward in the same row. The rows of teeth are, furthermore, located closer together as the size of the teeth in the rows becomes smaller so that, there are formed a series of circular grooves of triangular cross section lying between the rows of teeth, each groove being smaller in depth and top width than the next adjacent row inward toward the center of rotation. The number of teeth in the innermost row is selected to permit sufficient space therebetween to allow the pulp pieces to enter. The ratio of the number of teeth in all the other rows with respect to the number of teeth in each respective next inner row is approximately 2/ 1.

The impacting elements carried by the upper, stationary shredder plate 68 are formed in substantially the same manner as the elements on the lower shredder plate just described and are located so that each row projects into a groove between adjoining rows of elements on the lower shredder plate. They are further formed with their vertical faces facing the vertical faces of the teeth on the lower shredder plate. In addition, the impacting elements 72 on the upper and lower Each tooth or t shredder plates are positioned vertically in such fashion that the clearance between impacting elements on the two shredder plates as the lower plate is rotated is greatest at the inner edges of the plates where the elements are largest, the clearance for any vertical setting of the lower plate decreasing regularly outward along the radii of rotation to a value which is frequently only a few thousandths of an inch.

This provides a zone between the shredder plates 66 and 68 wherein, as pulp is fed to the apparatus through the central feed port 17 and impelled outward by centrifugal action and the vanes 64, the pulp is subjected to a mechanical fiber-separating action of progressively increasing intensity due to the greater number of elements in the peripheral rows and to the graduation in size and clearance of the two sets of impacting elements and, also, to the fact that the outer elements pass one another at a higher rate of speed than do the inner, larger elements due to their greater distance from the center of rotation.

In the operation of the apparatus shown in the drawing, whereby the new method can be practiced, the raw pulp which is to be bleached is fed into the apparatus through the feed port 17 with the rotor plate 57 and the attached lower shredder plate 66 rotating at a high speed. The pulp is immediately forwarded by the rotating vanees 64 outwardly along the top surfaces of the cone cap 62 and rotor plate 57 and is conveyed by centrifugal action into the fiber-separating zone between the shredder plates 66 and 68. Any particular bundle of fibers within the mass of pulp, e. g. as shown in dotted outline at 80 in Figure 2, is first engaged by the inner rows of teeth on one plate, e. g., the lower plate. The fiber bundle is then pressed into engagement with a pair of the teeth, e. g., the teeth 72, due to the relative motion with respect thereto of a tooth of the other plate, such as that also illustrated in dotted outline in Figure 2. The fiber bundle 80 is thus urged by a tooth of one plate, between the teeth of the other plate and, during the process, the bundle is flexed or bent in a manner tending to separate the fibers of the bundle from one another but not to break them. This flexing and bending of the fibers is repeated with an ever-increasing intensity and around a shorter and shorter radius as the fiber bundles progress through the fiber-separating zone.

As the fiber bundle is released momentarily after it passes between any particular set of teeth, it tends to straighten itself, due to its natural resiliency, into approximately its original shape and moves a short distance toward the periphery of the plates both because of centrifugal action and the effect of the impacting elements upon it and also because of the large volume of air which is automatically drawn into the apparatus through the feed port 17 and which is forwarded along with the fibers toward the periphery of the plates.

T he strong stream of air not only assists in moving the fibers through the zone, but tends to keep them somewhat aligned so that they do not become entangled upon the several teeth and also so that they are free to rotate on their longitudinal axes between bendings. Such rotation causes the bundle to be bent in various directions as it progresses through the zone and facilitates the separation of individual fibers from the bundles during repeated bending and flexing.

T he fiber-separating action increases in its intensity as the pulp moves outward through the fiber-separating zone due to the progressively decreased spacing between op posed surfaces of the plates, to closer tolerance between the two sets of impact elements, and to the smaller size and greater number and relative speed of the elements encountered by the pulp' as it passes through the zone Following its passage through the zone, it emerges from between the shredder plates and is impelled by means of the blades 65 through the circular channel in which the 13 blades travel and is subsequently discharged from the machine through the discharge port 18.

The pulp isthus subjected in the fiber-separating zone to a fiber-separating action of increasing intensity, it being understood that the fiber-separating action may, in the first portion of the zone, be largely that of separating the individual fibers from bundles of more or less adherent fibers, whereas as the fibers near the outer edge of the zone the action may be principally or even almost entirely that of separating non-adherent fibers from one another, the bundles having by that time been largely or completely separated into individual fibers.

The bleaching agent, or other treating agent, preferably in liquid form, is introduced into the pulp mass during its passage through the fiber-separating zone, the zone thus also becoming a fiber-treating zone. The agent is introduced at a point sulficiently far removed from the ends of the zone to provide for adequate atomization and distribution of the atomized solution through the pulp before it emerges from the fiber-separating and fibertreating zone. One convenient Way of introducing a liquid bleach into contact with pulp within the fiber-separating zone includes a feed pipe or conduit 73 which projects downward through a port in the upper housing member 11 and is threaded at its lower end to engage an internally threaded port in the upper shredder plate 68, the solution being fed through the conduit at a desired rate from a convenient storage and regulating means, not shown. In practice, it has sometimes been found convenient to introduce the bleaching agent into contact with the violently agitated pulp at several points approximately two-thirds of the distance through the fiber-separating zone measured from the point of entry of the pulp into the zone. Alternatively, a plurality of feed pipes can be employed for introducing the bleach into the fiber-separating zone at other suitably spaced intervals.

Example .I

In a typical instance of the operation of the process, an apparatus similar to that described in the previous paragraphs was employed. The row of largest teeth consisted of 18 teeth each inch high with its apex 8 inches from the center of rotation. The outermost row consisted of 372 teeth each 0.379 inch high with the apex of each 13 inches from the center of rotation. The lower shredder plate was rotated at a speed of 1750 R. P. M. with a maximum clearance of approximately A inch of the largest teeth at the inner edge of the shredder plates decreasing regularly to a minimumclearance of approximately A inch of the smallest teeth at the outer edge of the shredder plates.

Ground wood pulp consisting of approximately 10 per cent spruce and 90 per cent poplar containing 40 per cent of fibers on a dry basis was fed continuously into the machine at the rate of 1.25 (0.5 ton bone dry fiber) tons per hour. A bleaching solution was prepared by mixing 7080 pounds of water, 270 pounds of 50 per cent aqueous hydrogen peroxide and 1000 pounds of sodium silicate solution (12 per cent Na O). The bleaching solution, which contained 1.62 per cent actual hydrogen peroxide, was fed into the fiber-separating zone of the machine into contact with the pulp passing therethrough at a point about two-thirds of the way through the zone with respect to the direction of flow of the pulp at the rate of 50 gallons (417 lb.) of solution per hour. The temperature of both the pulp and the bleaching solution was about 75 degree Fahrenheit. 1

The pulp issuing from the fiber-separating zone had a fiber content of 34.4 per cent on a dry basis and a pH between 9.5 and 10. The pulp was packaged immediately for storage. Samples were taken directly from the pulp issuing from the machine from time to time and its brightness determined using the General Electric Refiectance Meter. Samples taken directly from the machine had a brightness as determined using .a General Electric Reflectance Meter'S to 12 points higher than the unbleached pulp.

Specimen packages of the bleached pulp were opened from time to time and the brightness of the pulp determined. It was found that the brightness increased continuously and appreciably during storage but at a decreasing rate, reaching an average maximum increase of about 16 points after about three days. At the end of three days the pH of the pulp was about 6.8. Samples of the bleached pulp examined after about three months indicated that no reversion in brightness occurred on long storage.

Example 2 Ground wood pulp consisting of a mixture of approximately 60 per cent poplar, 30 per cent spruce and 10 per cent balsam and containing 38 per cent of fibers on a dry basis was fed continuously into the machine used in Example 1. A bleaching solution was prepared by mixing in the order given 46,228 pounds of water, one pound of magnesium sulfate, 1000 pounds of sodium silicate solution (12 per cent N320), 191 pounds of 50 per cent aqueous hydrogen peroxide and 175 pounds of sodium peroxide. 'The bleaching solution thus prepared was fed into contact with the pulp passing through the fiber-separating zone of the machine'as before at the rate of 570 gallons (4760 pounds) per ton of fibers calculated on a bone dry basis. The temperatureof both the pulp and bleaching solution was about degrees Fahrenheit. The pulp issuing from the fiber-separating zone had a pH between 9.5 andlO. An increase in brightness of the pulp comparable to that of Example 1 was obtained.

It should be mentioned in connection with the operation of the apparatus shown in the drawing that it has been observed that when the machine is operated as described not only are the fibers of the wood separated completely from oneanother into substantially individual fibers, but also the pulp is deshived to a much greater degree than it has hitherto been possible to accomplish. At the same time it appears that the individual fibers are not broken unduly, as evidenced ,by photo-micrographs and screen classification tests.

Furthermore, and unexpectedly, it has ben observed that when the machine is adjusted to provide only a very small clearance, e. g., inch or less, at the outer edge of the fiber-separating zone the pulp is fibrillated and the fibers are curled to such an extent that they can be felted readily. The degree of fibrillation and curlation of the fibers which can be obtained readily in this way appears to be gerater than that obtained heretofore and the modified fibers appear to have utility not hitherto suspected of wood fibers.

Example 3 A quality of partially digested poplar wood chips was withdrawn from a batch type digester and drained. The drained chips were then run through the shredder used in the previous examples, which was adjusted so of well separated fibers, the entire mass being in a con- I dition for ready and rapid completion of the digestion process.

Example 4 The shredder employed in Example 1 was used in the treatment of sugar cane bagasse, first with dilute cane juice and then with water, as steps in a process for extracting sugar from the cane in acocrdance with the procedure given below. The shredder was run at a speed of 1775 R. P. M. in each treatment and the rate of how of the respective treating fluid was adjusted to provide uniform flow of fluid and bagasse through the machine during each treating step.

Sugar cane was chopped into small pieces. The chopped cane contained 13.9 per cent sugar, 10 per cent fiber and about 75 per cent water. Eight hundred forty-seven pounds of the chopped cane containing 118.2 pounds sugar, 84.7 pounds of fiber and 635.2 pounds of water was passed through the shredder to separate the fibers. No treating agent was employed in this step. This fiberseparating step was carired out at the rate of about 61 operation there was obtained 210 pounds of bagasse containing 49 per cent moisture and 646 pounds of juice having a BriX hydrometer reading corresponding to 17.05 per cent of sugar and a polysaecharide content, calculated as sugar, of 14.2 per cent. The sugar in the juice as calculated from the polysaccharide determination con- :i.

sisted of 91.73 pounds or 77.6 per cent of that originally in the cane.

The 210 pounds of bagasse obtained from the first pressing operation was treated at the rate of about 42.5

tons per day in the shredder with approximately 182 U pounds of a very dilute sugar solution obtained from the pressing in another opertaion of a more completely extracted portion of bagasse.

The product from the first treating operation was submitted to a second pressing operation, 11 pounds of steam being condensed in the product in the press to warm it. There were thus obtained 193 pounds of bagasse containing 53 per cent of water and 210 pounds of juice having a sugar content by Brix hydrometer of 8.8 per cent and by polysaccharide determination of 6.4 per cent. The amount of sugar in the juice as calculated from the polysaccharide determination amounted to 15.11 pounds or 11.6 per cent of that present in the original cane.

The 193 pounds of bagasse obtained from the second pressing opertaion was then subjected to a second treating operation at the rate of about 47 tons per day in the shredder with about 160 pounds of water. The treated fibrous mass had a water content of 74 per cent.

The treated fibrous mass resulting from the second treating operation was pressed as before, 10 pounds of steam being condensed in the mixture during pressing to increase its temperature. As a result of this third pressing operation, there was obtained 186.5 pounds of bagasse containing 55 per cent of water and per cent or 83.9 pounds, on a dry basis, of fiber containing a very small proportion of residual sugar. The juice obtained from the third pressing operation weighed 176 pounds and had a sugar content as determined by Brix hydrometer of 4.1 per cent and, as calculated from a polysaccharide determination, of 3.6 per cent. On the basis of the polysaccharide determination, the sugar in the juice amounted to 4.6 pounds or 3.9 per cent of that originally present in the cane.

As a result of this series of operations, there was obtained 93.1 per cent of the sugar present in the treated cane in the form of a juice from which the sugar could be recovered by conventional procedures. There was also obtained about 99 per cent of the fiber in the untreated cane as a uniform purified product in which the individual fibers were all substantially separated from one another and which was in. a form especially well adapted to further processing, such as in the making of fiber board, paper and the like.

Example 5 One thousand parts by weight (dry basis) of sulphite pulp having a consistency of 40 per cent was treated, in the same apparatus by substantially the same procedure employed in Example 1, with a solution of 20 parts of sodium chlorite per cent) in 625 parts of water. The treated pulp was again forwarded through the same apparatus and treated in the same manner as before with a solution of 48.7 parts of sodium hypochlorite in 625 parts of water. The treated pulp was then stored for a period of three hours at 104 degrees Fahrenheit.

Hand sheets of paper were prepared from the bleached and unbleached pulp. The brightness of each sheet was The brightdetermined using standard TAPPI methods. ness was increased by the treatment from 78.6 G. E. for the unbleached pulp to 88.9 G. E. for the bleached pulp.

Similar results are obtained by treating the pulp during a single pass through the treating zone in the equipment with both the sodium chlorite and the sodium hypochlorite solutions, the former being introduced into the zone nearer the point of entry of the pulp than the latter.

I claim:

I. The process for treating a bulk, unoriented fibrous substance with a treating agent, which includes: forwarding a mass of bulk, unoriented fibers through a fiberseparating and fiber-treating zone; subjecting the fibers in the zone to a mechanical fiber-separating action of progressively increasing intensity to separate substantially the fibers from one another, introducing a fiber-treating agent into a region within the zone intermediate the regions of least and of greatest fiber-separating action to contact substantially the surfaces of the separated fibers with the treating agent; and withdrawing fibers having the treating agent substantially evenly dispersed therein from the fiber-separating and fiber-treating zone.

2. The process of claim 1 wherein the fibers are forwarded through, and the treating agent is introduced into the fiber-separating and fiber-treating zone continuously and at substantially predetermined rates.

3. The continuous process for treating a bulk, unoriented fibrous substance with a treating agent, which includes: forwarding continuously a mass of bulk, unoriented fibers substantially free of liquid phase substances through a fiber-separating and fiber-treating zone; subjecting the fibers in the zone to a mechanical fiberseparating action of progressively increasing intensity to separate substantially the fibers from one another; introducing continuously a fluid treating agent into a region within the zone intermediate the regions of least and of greatest fiber-separating action to atomize the fluid agent and to contact substantially the surfaces of the separated fibers with the atomized agent; and withdrawing continu ously from the zone fibers coated substantially uniformly with the treating agent.

4. The method of claim 3 wherein the treating agent is introduced into a region within the fiber-separating zone located between about 25 per cent and about per cent of the distance through the zone, measured from the point of entry of the fibers into the zone.

5. In a continuous method for bleaching cellulosic fibers, the steps which include: forwarding continuously at mass of cellulosic fibers substantially free of liquid phase water through a fiber-separating zone; subjecting the fibers in the fiber-separating zone to a fiber-separating action of progressively increasing intensity to separate substantially the fibers from one another; introducing continuously a fiuid bleach into a region within the fiber-separating zone intermediate the regions of least and of greatest fiberseparating action to contact substantially the surface of the separated fibers with the bleach; and subsequently con tinuously withdrawing fibers having the bleach substantially evenly dispersed therein from the fiber-separating zone.

6. In a continuous method for bleaching cellulosic fibers, the steps whichinclude: forwarding continuously a mass of cellulosic fibers substantially free of liquid phase water through a fiber-separating zone; subjecting the fibers in the fiber-separating zone to a mechanical fiber-separating action of progressively increasing intensity to separate substantially the fibers from one another; introducing continuously a liquid bleach into a region Within the fiber-separating zone substantially removed from the region of greatest fiber-separating action to atomize the liquid bleach and contact substantially the surface of the separated fibers with the atomized bleach; and subsequently continuously withdrawing fibers having the bleach substantially evenly dispersed therein from the fiber-separating zone.

7. In a continuous method for bleaching wood pulp, the steps which include: forwarding continuously a mass of wood pulp having a fiber content of at least about per cent on the dry basis through the fiber-separating zone; subjecting the pulp in the fiber-separating zone to a fiberseparating action of progressively increasing intensity to separate substantially the fibers from one another; introducing continuously a liquid bleach into a region within the fiber-separating zone substantially removed from the region of greatest fiber-separating action to atomize the liquid bleach and contact substantially the surface of the separated fibers with the atomized bleach; and subsequently continuously withdrawing pulp having bleach substantially evenly distributed therethrough from the fiber-separating zone.

8. The method of claim 7 wherein the wood pulp contains from about 30 to about 90 per cent or more of fibers on a dry basis.

9. The method of claim 7 wherein the region in which the bleach is introduced into the fiber-separating zone is about two-thirds of the distance from the region of least fiber-separating action to the region of greatest fiber-separating action.

10. The method of claim 7 wherein the bleach is an aqueous solution.

11. The method for treating a bulk, unoriented fibrous substance with a treating agent which includes: forwarding continuously a mass of bulk, unoriented fibers substantially free of liquid phase substances through a fiber-separating and fiber-treating zone; forwarding a gaseous atmosphere through the zone concurrently with the fibers; subjecting the fibers in the zone to a mechanical fiber-separating action of progressively increasing intensity to separate substantially the fibers from one another, the proportion of fibers with respect to the atmosphere being such that the individual fibers immediately prior to issuing from the zone tend to float freely in the atmosphere except for the efiect of the fiber-separating action; introducing continuously a fluid treating agent into a region within the zone intermediate the regions of least and of greatest fiber-separating action to atomize the agent and to contact substantially the entire surfaces of the separated fibers with the agent; and withdrawing continuously from the zone fibers coated substantially uniformly with the treating agent.

12. The method of claim 11 wherein the treating agent is introduced into a region within the fiber-separating zone located between about 25% and about 85% of the distance through the zone, measured from the point of entry of the fibers into the zone.

13. The method for processing a bulk, unoriented fibrous substance comprised at least in part of bundles of adherent fibers to separate the fibers from one another and to treat them with a treating agent, which includes: forwarding continuously a gaseous atmosphere and a mass of bulk, unoriented fibers substantially free of liquid phase substances, and comprised at least in part of bundles of adherent fibers, through a fiber-separating and fiber-treating zone; subjecting the bundles of fibers in the zone to a rapid and repeated bending and impacting fiber-separating action of progressively increasing intensity to separate the bundles, while in a region of the zone of less than maximum fiber-separating action, substantially into individual fibers and teed-mingle the individual fibers and the atmosphere thoroughly together, the fiber-separating action at least withinthe region of the zone providing the. most intense fiber-separating. action effecting principally the rapid andrepeated separation from one another of non-adherent," substantially individual fibers whereby the individual "fibers tend to .be free-floating in the atmosphere except for the effect of the fiber-separating action; introducing continuously afluid treating agent into a region within the zone intermediate the region of least and of greatest fiber-separating action to atomize the agent and to contact substantially the entire surfaces of the separated fibers with the agent; and withdrawing continuously from the zone fibers coated substantially uniformly with the treating agent.

14. The method of claim 13 wherein the treating agent is introduced into a region within the zone wherein the bundles of fibers have been separated substantially into individual fibers but wherein the fiber-separating action is less intense than that to which the fibers are subjected immediately prior to their issuance from the zone.

15. The method for treating a bulk, unoriented fibrous substance with a treating agent which includes: forwarding continuously a mass of bulk, unoriented fibers through a fiber-separating and fiber-treating zone; forwarding a gaseous atmosphere through the zone concurrently with the fibers; subjecting the fibers in the zone to a mechanical fiber-separating action of progressively increasing intensity to separate substantially the fibers from one another, the proportion of fibers with respect to the atmosphere being such that the individual fibers immediately prior to issuing from the zone tend to float freely in the atmosphere except for the eflfect of the fiber-separating action; introducing continuously a fluid treating agent into a region within the zone intermediate the regions of least and of greatest fiber-separating action to atomize the agent and to contact substantially the entire surfaces of the separated fibers with the agent; and withdrawing continuously from the zone fibers coated substantially uniformly with the treating agent.

16. The process for treating a bulk, unoriented fibrous substance with a treating agent, which includes: forwarding a mass of bulk, unoriented fibers through a fiber-separating andfiber-treating zone; subjecting the fibers in the zone to a mechanical fiber-separating action of progressively increasing intensity to separate substantially the fibers from one another; introducing a first fiber-treating agent into a first region within the zone intermediate the regions of least and of greatest fiber-separating action to contact substantially the surfaces of the separated fibers with the first treating agent; introducing a second fibertreating agent into a second region spaced from said first region and within the zone intermediate the regions of least and greatest fiber-separating action to contact substantially the surfaces of the separated fibers with the second treating agent; and withdrawing fibers having the treating agents substantially evenly dispersed therein from the fiber-separating and fiber-treating zone.

17. The method of claim 16 wherein the fibers are forwarded continuously into the fiber-separating and fibertreating zone and the treating agents are continuously introduced into a region within the fiber-separating zone located between about 25% and about of the distance through the zone, measured from the point of entry of the fibers into the zone.

18. The process of claim 17 wherein the fibers are substantially free of liquid phase substances.

(Other references on following page) 

1. THE PROCESS FOR TREATING A BULK, UNORIENTED FIBROUS SUBSTANCE WITH A TREATING AGENT, WHICH INCLUDES: FORWARDING A MASS OF BULK, UNORIENTED FIBERS THROUGH A FIBERSEPARATING AND FIBER-TREATING ZONE; SUBJECTING THE FIBERS IN THE ZONE TO A MECHANICAL FIBER-SEPARATING ACTION OF PROGRESSIVELY INCREASING INTENSITY TO SEPARATE SUBSTANTIALLY THE FIBERS FROM ONE ANOTHER, INTRODUCING A FIBER-TREATING AGENT INTO A REGION WITHIN THE ZONE INTERMEDIATE THE REGIONS OF LEAST AND OF GREATEST FIBER-SEPARATING ACTION TO CONTACT SUBSTANTIALLY THE SURFACES OF THE SEPARATED FIBERS WITH THE TREATING AGENT; AND WITHDRAWING FIBERS HAVING THE TREATING AGENT SUBSTANTIALLY EVENLY DISPERSED THEREIN FROM THE FIBER-SEPARATING AND FIBER-TREATING ZONE. 